Green tea polyphenol epigallocatechin-3-gallate shows therapeutic antioxidative effects in a murine model of colitis

Background and aims: Leukocyte infiltration, up-regulation of proinflammatory cytokines and severe oxidative stress caused by increased amounts of reactive oxygen species are characteristics of inflammatory bowel disease. The catechin (2R,3R)-2-(3,4,5-Trihydroxyphenyl)-3,4-dihydro-1(2H)-benzopyran-3,5,7-triol-3-(3,4,5-trihydroxybenzoate), named epigallocatechin-3-gallate, EGCG, has been demonstrated to exert anti-inflammatory and antioxidative properties, reducing reactive oxygen species in the inflamed tissues. The aim of this study was to evaluate the therapeutic effects of EGCG in a murine model of colitis induced by oral administration of dextran sodium sulfate. Methods: Mice received a daily oral administration of 6.9 mg/kg body weight EGCG or Piper nigrum (L.) alkaloid (2E,4E)-5- (1,3-benzodioxol- 5-yl)-1-piperidin-1-ylpenta-2,4-dien-1-one, named piperine (2.9 mg/kg body weight) or the combination of the both piperine was used in this combination to enhance the bioavailability of EGCG. Results: In vivo data revealed the combination of EGCG and piperine to significantly reduce the loss of body weight, improve the clinical course and increase overall survival in comparison to untreated groups. The attenuated colitis was associated with less histological damages to the colon and reduction of tissue concentrations of malondialdehyde, the final product of lipid peroxidation. Neutrophils accumulation indicator myeloperoxidase was found to be reduced in colon tissue, while antioxidant enzymes like superoxide dismutase and glutathione peroxidase showed an increased activity. In vitro, the treatment with EGCG plus piperine enhanced the expression of SOD as well as GPO and also reduced the production of proinflammatory cytokines. Conclusion: These data support the concept of anti-inflammatory properties of EGCG being generally beneficial in the DSS-model of colitis, an effect that may be mediated by its strong anti-oxidative potential. (C) 2011 European Crohn's and Colitis Organisation. Published by Elsevier B.V. All rights reserved.